The Pentagon's top military officer oversaw a secret war game this month to evaluate the two primary military options that have been put forward by the Pentagon and are being weighed by the Obama administration as part of a broad-based review of the faltering Afghanistan war, senior military officials said.

The exercise, led by Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, examined the likely outcome of inserting 44,000 more troops into the country to conduct a full-scale counterinsurgency effort aimed at building a stable Afghan government that can control most of the country. It also examined adding 10,000 to 15,000 more soldiers and Marines as part of an approach that the military has dubbed "counterterrorism plus."

Both options were drawn from a detailed analysis prepared by Gen. Stanley A. McChrystal, the senior commander in Afghanistan, and were forwarded to President Obama in recent weeks by Defense Secretary Robert M. Gates.

The Pentagon war game did not formally endorse either course; rather, it tried to gauge how Taliban fighters, the Afghan and Pakistani governments and NATO allies might react to either of the scenarios. Mullen, a key player in the game, has discussed its conclusions with senior White House officials involved in the discussions over the new strategy.

One of the exercise's key assumptions is that an increase of 10,000 to 15,000 troops would not in the near future give U.S. commanders the forces they need to take back havens from the Taliban commanders in southern and western Afghanistan, where shadow insurgent governors collect taxes and run court systems based on Islamic sharia law.

"We were running out the options and trying to understand the implications from many different perspectives, including the enemy and the Afghan people," said a senior military official, who was granted anonymity to discuss the classified game.

The Obama administration initiated a major review of its war strategy in late September after questions emerged about the legitimacy of the Aug. 20 Afghan elections, which were marred by allegations of widespread fraud, and a troubling update on the progress of the war by McChrystal. He warned that unless the United States moved quickly to wrest momentum from the Taliban, defeating the insurgency in Afghanistan might no longer be possible.

What was intended to be two or three weeks of intensive White House meetings has stretched on for almost a month. Obama and his national security advisers have sorted through the military and civilian aspects of the war, building toward a decision that many on the outside have urged be made sooner rather than later.

Last week, the president concluded the five planned review sessions, roughly 15 hours in all, with top advisers in the Situation Room.

McChrystal's analysis suggests that 44,000 troops would be needed to drive Taliban forces from populated areas and to hold them until Afghan troops and government officials can take the place of U.S. and NATO forces. The extra troops would allow U.S. commanders to essentially triple the size of the American forces in the southern part of the country, where the Taliban movement originated and where the insurgents have their strongest base of support.

McChrystal would also use the additional troops to bolster the effort in eastern Afghanistan, which has long been a focus of the U.S. military, and push additional troops into western Afghanistan, where the military has maintained a tiny presence and where the Taliban has made inroads, U.S. officials said. A surge of 44,000 soldiers and Marines would also allow McChrystal to designate a brigade of about 5,000 soldiers to train and advise the Afghan army and police forces, accelerating their growth.

The increase of 10,000 to 15,000 soldiers would give McChrystal one U.S. advisory brigade of about 5,000 troops to speed the development of Afghan forces and a large number of support forces to include engineers, route-clearance teams and helicopters. McChrystal's analysis also suggested the option of increasing the number of troops by 80,000, but that isn't drawing serious consideration.

In television interviews Sunday, lawmakers outlined broad partisan differences over how many troops are needed in Afghanistan. Republicans have voiced strong support for granting McChrystal's request for more troops, and urged that it be done quickly.

"I'm afraid that with every passing day, we risk the future success of the mission," Sen. Jon Kyl (R-Ariz.) said on "Fox News Sunday."

Sen. James Webb (D-Va.) disagreed, calling the decision-making process "very proper and smart." The administration's lengthy deliberations are "what we need, because we're going to end up living with the results for a good period of time," Webb said on CNN's "State of the Union."

The administration's internal deliberations have emphasized that unless the Afghan government dramatically improves its performance, the Taliban will continue to find support. Administration officials said Obama's decision will consider a much broader range of options than the number of troops. At nearly every meeting in the White House Situation Room, McChrystal has been joined on the video screens at the end of the table by Karl W. Eikenberry, the U.S. ambassador to Kabul, and Anne W. Patterson, his counterpart in Pakistan.

One question being debated is whether more U.S. troops would improve the performance of the Afghan government by providing an important check on corruption and the drug trade, or would they stunt the growth of the Afghan government as U.S. troops and civilians take on more tasks that Afghans might better perform themselves. Another factor is cost. The Pentagon has budgeted about $65 billion to maintain a force of about 68,000 troops, meaning that each additional 1,000 U.S. soldiers in Afghanistan would cost about $1 billion a year.

Administration officials say Obama might settle on a plan but delay announcing it until after a runoff in the Afghan national elections, scheduled for Nov. 7. The president is to begin a 10-day trip to Asia on Nov. 11.

Early this month, McChrystal was told to delay a planned Washington trip until Obama had finished gathering facts on the way ahead. "When you see McChrystal in town," along with Eikenberry and Patterson, a senior administration official said, "you'll know that [Obama] is close to a decision."